The announcement, made by Nats president of baseball operations and general manager Mike Rizzo, completes the three-team trade in which Washington received right-hander Joe Ross and a player to be named from the Padres last Dec. 18. The Nationals sent outfielder Steven Souza Jr. and Minor League left-hander Travis Ott to the Tampa Bay Rays as a part of the trade.
"It was a unique strategy we had when we made the trade," Rizzo said. "It was really unprecedented and creative by our front office to identify and get a player that we wanted all along."
The 21-year-old Turner joins the Nationals' organization as their No. 3 prospect after batting .322 (73-for-227) with 13 doubles, three triples, five home runs and 35 RBIs while with San Diego's Double-A affiliate, the San Antonio Missions. Turner's .322 batting average ranked third in the Texas League at the time of the trade.
Turner was named the Padres' Minor League Defensive Player of the Year in 2014 after posting a .984 fielding percentage in 50 games at shortstop between Class A Short-Season Eugene and Class A Fort Wayne.
"He's a guy that's got a good approach at the plate," Rizzo said. "He's got a good eye. He's a very poised hitter. He should be a high-average, high-on-base percentage guy who profiles somewhere at the top of the order, a guy that runs extremely well and has the chance to steal a base."
Due to the odd circumstances surrounding the trade, the Nats couldn't speak with Turner before the acquisition could be made official. However, the team continued to keep tabs on him through scouting. Rizzo credited the Padres organization for how it handled Turner, who technically wasn't its player anymore.
"We've had guys in there to scout him periodically," Rizzo said. "We made an assignment for several of our professional scouts to make their way through San Antonio to see him play. [The Padres] treated him like the prospect that he is. I give them a lot of credit for not hindering his progress and his development by treating him like any other prospect. That was something that we discussed when we made the trade and they did things that were really in the best interest of Trea."
Rizzo and the Nationals were high on Turner going into the 2014 Draft.
"The current [Padres] regime in there didn't draft the player," Rizzo said. "They didn't have a lot of ownership to the player. I'm not sure how much they knew the player as an amateur. We loved him as an amateur player high on our [Draft] board."
Brandon Curry is an associate reporter for MLB.com.